Airworthiness Directives; Bombardier Model CL-600-2B19 (Regional Jet Series 100 & 440) Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain Bombardier Model CL-600-2B19 (Regional Jet Series 100 & 440) airplanes. This AD requires revising the Airworthiness Limitations section of the Instructions for Continued Airworthiness of the Canadair Regional Jet Maintenance Requirements Manual by incorporating new repetitive detailed inspections of the secondary load path indicator for the horizontal stabilizer trim actuator (HSTA). This AD is prompted by a report of a potential failure of the horizontal stabilizer trim actuator (HSTA) secondary nut in conjunction with a latent failure of the HSTA primary load path discovered during sampling program activities. We are issuing this AD to detect and correct latent failure of the primary load path of the HSTA, which, in conjunction with a failure of the HSTA secondary nut, could result in loss of horizontal trim control and consequent reduced controllability of the airplane.